SCIENCE

The enactment of medical cannabis access laws is associated with significant reductions in prescription opioid use among Medicaid enrollees, according to just-published data in the journal Addiction.

Investigators with the University of California at San Diego assessed the relationship between medical cannabis legalization and opioid use among Medicaid enrollees over a period of 21 years (1993 to 2014).

Authors reported, “For Schedule III opioid prescriptions, medical cannabis legalization was associated with a 29.6 percent reduction in number of prescriptions, 29.9 percent reduction in dosage, and 28.8 percent reduction in related Medicaid spending.” This correlation remained after authors controlled for potential confounders, such as the establishment of prescription drug monitoring programs and variations in patients’ income.

By contrast, authors did not report similar changes in enrollees’ use of Schedule II opioid drugs, like Oxycodone. Authors speculated that this result may be because physicians are more reticent to recommend medical cannabis options to these patients.

They concluded: “In this study, we found that statewide medical cannabis legalization implemented in 1993-2014 in the US was associated with close to 30 percent reductions in Schedule III opioids received by Medicaid enrollees.. … It was estimated that, if all the states had legalized medical cannabis by 2014, Medicaid annual spending on opioid prescriptions would be reduced by 17.8 million dollars.”

Their findings are similar to those of numerous other observational studies – such as those here, here, and here – finding that medical marijuana regulation is correlated with reductions in overall opioid-related use, drug spending, abuse, hospitalization, and mortality. Separate data evaluating prescription drug use trends among individual patients enrolled in state-licensed medical marijuana programs is consistent with this conclusion, finding that many subjects reduce or eliminate their use of opioids following enrollment.

The abstract of the new study, “Medical cannabis legalization and opioid prescriptions: Evidence of US Medicaid enrollees during 1993-2014,” appears online here.

The FDA’s decision was not unexpected, as the proprietary extract formulation — developed by the British biotechnology firm GW Pharmaceuticals — had previously demonstrated safety and clinical efficacy at reducing seizure frequency in several placebo-controlled trials. Epidiolex had previously received Fast Track Designation and Orphan Drug Status from the FDA. It is the fourth marijuana-based medicine to receive US FDA approval — joining dronabinol (aka Marinol), nabilone (aka Cesamet), and liquid synthetic THC (aka Syndros). However, Epidiolex is the first FDA-approved medicine containing plant-derived, non-synthetic cannabinoids.

Commenting on the agency’s decision, NORML Deputy Director Paul Armentano said: “The FDA’s approval of this plant-derived medicine provides an additional option to patients seeking the therapeutic benefits of cannabis. However, it remains to be seen whether physicians will be comfortable prescribing this new agent to those patients who may benefit from it, and whether it will be priced in a range that patients may afford.” According to the New York Times, analysts expect Epidiolex to cost $2,500 to $5,000 a month.

He added: “We anticipated that Epidiolex will be the first of many potential FDA-approved medicines based on the cannabis plant. Nonetheless, these alternatives should not be regulated as options to replace the use and regulation of herbal cannabis — a product that humans have used safely and effectively as a medicine for thousands of years and is approved today by statute in 30 states.”

Federal agencies have 90 days to determine the scheduling of Epidiolex. The new drug is anticipated to become available to patients later this fall. In clinical trials, patients administered Epidiolex, on average, obtained a 40 percent reduction in seizure frequency.

Lennox-Gaustaut syndrome is estimated to account for between one and four percent of all cases of childhood epilepsy. Dravet syndrome is estimated to effect about 1 in 40,000 people.

Despite today’s approval, the FDA acknowledged in a statement that the cannabidinoid CBD still remains classified at this time as a schedule I controlled substance, and that the agency is “prepared to take action when we see the illegal marketing of CBD-containing products with serious, unproven medical claims.” FDA Commissioner Scott Gottlieb further added: “This is the approval of one specific CBD medication for a specific use. … [T]his is not an approval of marijuana or all of its components.”

More than two-thirds of chronic pain patients registered to legally access medical cannabis products substitute marijuana for prescription opioids, according to data published in The Journal of Headache and Pain.

Investigators from the United States and Canada assessed the use of medical cannabis and prescription drugs in a cohort of over 2,000 Canadian patients licensed to access marijuana products. Among those patients with a primary diagnosis of chronic pain, 73 percent reported substituting cannabis in place of opioids. Among those patients diagnosed specifically with headache/migraine, cannabis was frequently reported as a substitute for other medications – including opiates (43 percent), anti-depressants (39 percent), NSAIDS (21 percent), triptans (8 percent), and anti-convulsants (8 percent).

“Most patients in the pain groups reported replacing prescription medications with medicinal cannabis, the most common of which were opiates/opioids across all patient groups,” authors concluded. “This is notable given the well-described ‘opioid-sparing effect’ of cannabinoids and growing abundance of literature suggesting that cannabis may help in weaning from these medications and perhaps providing a means of combating the opioid epidemic.”

The study’s findings are consistent with those of numerous others finding that patients in medical cannabis access programs significantly reduce or eventually eliminate their use of opioid analgesics over the long-term.

Full text of the study, “Patterns of medicinal cannabis use, strain analysis, and substitution effect among patients with migraine, headache, arthritis, and chronic pain in a medicinal cannabis cohort,” appears online here.

Patients enrolled in New York state’s medical cannabis program reduce their use of opioids and spend less money on prescription medications, according to data published online in the journal Mental Health Clinician.

Investigators from the GPI Clinical Research in Rochester and the University of Buffalo assessed trends in patients’ medical cannabis and prescription drug use following their enrollment into the state’s marijuana access program.

On average, subjects’ monthly analgesic prescription costs declined by 32 percent following enrollment, primarily due to a reduction in the use of opioid pills and fentanyl patches. “After three months treatment, medical cannabis improved [subjects’] quality of life, reduced pain and opioid use, and lead to cost savings,” authors concluded.

The full text of the study, “Preliminary evaluation of the efficacy, safety, and costs associated with the treatment of chronic pain with medical cannabis,” appears online here. NORML’s fact-sheet highlighting the relevant, peer-reviewed research specific to the relationship between cannabis and opioids is available online here.

The frequent use of cannabis is not associated with changes in brain structure, according to data published online ahead of print in the journal Addiction.

An international team of scientists from Australia, the United Kingdom, and the United States assessed the relationship between habitual cannabis exposure and grey matter volumes in seven regions of the brain – including the thalamus, hippocampus, amygdala, and the nucleus accumbens – in two large population-based twin samples.

Researchers reported, “[N]ormal variation in cannabis use is statistically unrelated to individual differences in brain morphology as measured by subcortical volume.”

By contrast, the repeated use of nicotine was positively associated with significantly smaller thalamus volumes in middle-aged males.

Authors concluded: “This is the largest exploratory analysis integrating brain imaging with self-report cannabis and comorbid substance use data. After correcting for multiple testing, there was no effect of cannabis use on the volume at any subcortical region of interest in young adults or middle-aged males. … In the context of expanding medicalization and decriminalization and the concerns surrounding the consequences of increased cannabis availability, our findings suggest that normal variation in cannabis use is statistically unrelated to brain morphology as measured by subcortical volumes in non-clinical samples.”

The findings are consistent with those of prior brain imaging studies reporting that cannabis exposure appears to have little to no significant adverse impact upon brain morphology — particularly when compared to the dramatic effects associated with the alcohol exposure.

The study’s findings fail to replicate those of a well-publicized 2014 paper which alleged that even casual marijuana exposure may be linked to brain abnormalities, particularly in the amygdala.

Last week, a meta-analysis of 69 separate studies reported that cannabis exposure in adolescents and young adults is not associated with any significant, residual detrimental effects on cognitive performance. The results from a pair of recently published longitudinal twin studies similarly report that cannabis use is not independently associated with any residual change in intelligence quotient or executive function.

An abstract of the study, “Testing associations between cannabis use and subcortical volumes in two large population-based samples,” appears online here.